Here’s a timely reminder that Federal Rule of Evidence 702 (the basis of the Supreme Court’s famous Daubert decision) imposes a four-part test. For expert opinion testimony to be admissible, the fact that the expert has “scientific, technical, or other specialized knowledge [that] will help the trier of fact to understand the evidence or to determine a fact in issue” [Fed. R. Evid. 702(a)] is necessary, but not sufficient. The testimony must also be (b) “based on sufficient facts or data” and (c) “the product of reliable principles and methods”; and (d) the expert must have “reliably applied the principles and methods to the facts of the case.” The U.S. Court of Appeals for the Tenth Circuit recently affirmed the exclusion of a plaintiff’s expert’s testimony based on factors (c) and (d):
“It is not enough to have a knowledgeable expert leap to the conclusions a party would like the jury to be exposed to. Rather, there must be a reliable and identifiable basis for the expert’s opinions, grounded in the evidence and in the practices and standards of the particular discipline involved. That basis is lacking as to the proffered opinions of Mr. Blackwell.”
Schulenberg v. BNSF Railway Company (10th Cir., 12/27/2018), https://www.ca10.uscourts.gov/opinions/18/18-6003.pdf.